Seneca City Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Seneca City Park clear sky chart from 2005-11-06 to 2024-03-06.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	10% 7% 3 6% 5% 3 4 4 5% 7% 45%	78604
	Night	10% 7% 3 6% 5% 2 4 4 5% 7% 49%	80950
Transparency	Day	39% 6% 12% 25% 16% 2	78327
	Night	36% 6% 12% 26% 18% 3	80747
Seeing	Day	13% 10% 30% 29% 15% 3	14707
	Night	13% 10% 34% 33% 10% 1	24796

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	11% 11% 5% 11% 9% 4 5% 4 5% 6% 29%	2847
	11th to 20th	Day	8% 11% 4 9% 7% 3 6% 4 4 5% 37%	2850
	21st to end	Day	9% 12% 6% 12% 6% 3 4 4 4 6% 35%	3135
February	1st to 10th	Day	10% 10% 5% 8% 5% 4 5% 4 4 7% 37%	1710
	11th to 20th	Day	10% 7% 4 8% 6% 3 4 4 6% 7% 42%	1721
	21st to end	Day	8% 9% 3 6% 6% 3 4 3 5% 7% 47%	1570
March	1st to 10th	Day	10% 9% 3 6% 4 3 4 4 4 6% 47%	2021
	11th to 20th	Day	15% 12% 4 6% 4 2 4 4 5% 7% 38%	1980
	21st to end	Day	16% 11% 5% 8% 6% 4 4 4 4 6% 31%	2178
April	1st to 10th	Day	14% 6% 3 5% 5% 3 4 4 4 6% 47%	2021
	11th to 20th	Day	12% 8% 3 6% 5% 2 5% 5% 5% 7% 40%	2202
	21st to end	Day	19% 7% 2 5% 5% 3 5% 4 5% 7% 38%	2340
May	1st to 10th	Day	14% 9% 3 6% 6% 3 5% 5% 5% 6% 37%	2340
	11th to 20th	Day	15% 7% 3 5% 4 3 5% 4 6% 8% 41%	2302
	21st to end	Day	15% 7% 3 6% 6% 4 5% 5% 6% 8% 35%	2531
June	1st to 10th	Day	6% 4 2 4 5% 3 5% 5% 6% 9% 52%	2430
	11th to 20th	Day	7% 4 2 4 5% 3 5% 5% 6% 9% 49%	2520
	21st to end	Day	7% 4 2 4 4 3 4 5% 7% 10% 49%	2370
July	1st to 10th	Day	9% 3 2 5% 4 3 5% 6% 7% 10% 46%	2340
	11th to 20th	Day	5% 4 2 4 5% 3 5% 6% 6% 8% 52%	2340
	21st to end	Day	6% 5% 2 5% 5% 3 5% 5% 7% 9% 49%	2546
August	1st to 10th	Day	7% 4 3 6% 5% 4 6% 6% 7% 7% 45%	2328
	11th to 20th	Day	8% 4 2 5% 4 2 4 4 5% 7% 53%	2301
	21st to end	Day	7% 4 2 4 5% 3 4 4 6% 7% 55%	2512
September	1st to 10th	Day	11% 3 2 3 4 3 4 5% 5% 6% 54%	2079
	11th to 20th	Day	9% 5% 2 5% 5% 3 5% 5% 4 8% 51%	1980
	21st to end	Day	9% 4 2 4 3 3 3 4 3 5% 58%	1980
October	1st to 10th	Day	13% 5% 2 4 4 2 4 3 5% 6% 52%	1846
	11th to 20th	Day	10% 5% 2 5% 3 2 3 3 3 5% 57%	1800
	21st to end	Day	12% 7% 2 4 4 2 3 4 3 6% 52%	1980
November	1st to 10th	Day	8% 5% 2 4 4 2 3 4 5% 7% 57%	1737
	11th to 20th	Day	10% 9% 2 4 4 2 3 3 4 6% 55%	1710
	21st to end	Day	12% 7% 4 5% 4 2 3 5% 4 6% 49%	1549
December	1st to 10th	Day	8% 6% 3 6% 6% 3 3 4 6% 8% 47%	1520
	11th to 20th	Day	8% 10% 4 8% 5% 3 4 4 4 6% 44%	1918
	21st to end	Day	14% 13% 7% 14% 6% 3 4 4 4 6% 25%	3070
January	1st to 10th	Night	8% 9% 4 14% 8% 3 4 4 4 6% 36%	4108
	11th to 20th	Night	8% 8% 4 7% 5% 3 7% 6% 4 5% 43%	4120
	21st to end	Night	13% 11% 5% 8% 5% 2 4 3 4 6% 38%	4532
February	1st to 10th	Night	11% 10% 4 7% 6% 3 5% 5% 5% 6% 39%	2470
	11th to 20th	Night	10% 7% 3 6% 6% 3 5% 4 5% 7% 45%	2364
	21st to end	Night	9% 7% 3 5% 4 3 4 4 5% 7% 48%	1884
March	1st to 10th	Night	9% 6% 3 6% 5% 2 4 4 5% 5% 51%	2053
	11th to 20th	Night	14% 9% 3 6% 4 2 3 4 5% 6% 44%	1980
	21st to end	Night	17% 11% 4 6% 5% 3 4 4 5% 6% 34%	2178
April	1st to 10th	Night	11% 5% 1 4 5% 3 4 4 5% 7% 51%	1937
	11th to 20th	Night	12% 8% 3 5% 5% 3 3 4 5% 5% 47%	1705
	21st to end	Night	17% 6% 2 5% 4 3 3 4 5% 7% 44%	1620
May	1st to 10th	Night	14% 7% 3 5% 5% 4 5% 5% 6% 7% 39%	1620
	11th to 20th	Night	15% 6% 2 4 4 2 3 4 4 7% 48%	1593
	21st to end	Night	12% 6% 3 4 5% 2 5% 4 5% 8% 45%	1745
June	1st to 10th	Night	5% 3 1 3 4 3 5% 4 5% 11% 55%	1522
	11th to 20th	Night	5% 4 1 3 3 2 4 6% 6% 10% 55%	1440
	21st to end	Night	5% 2 1 3 4 2 3 4 6% 10% 61%	1579
July	1st to 10th	Night	7% 4 2 3 4 2 4 5% 7% 9% 52%	1620
	11th to 20th	Night	3 2 2 3 4 2 5% 4 7% 8% 61%	1620
	21st to end	Night	5% 3 1 3 4 3 5% 5% 6% 11% 54%	1772
August	1st to 10th	Night	4 3 2 4 5% 3 5% 5% 5% 9% 56%	1611
	11th to 20th	Night	6% 3 1 5% 4 2 4 5% 6% 8% 57%	1600
	21st to end	Night	6% 4 2 4 3 2 3 4 5% 6% 61%	1844
September	1st to 10th	Night	9% 3 1 4 4 2 3 4 4 7% 58%	1878
	11th to 20th	Night	8% 4 2 4 4 2 4 4 4 7% 58%	1980
	21st to end	Night	7% 4 2 3 4 2 3 3 4 5% 63%	1980
October	1st to 10th	Night	12% 5% 2 4 4 2 3 4 5% 6% 52%	2095
	11th to 20th	Night	13% 6% 1 3 3 2 3 3 3 6% 58%	2160
	21st to end	Night	12% 8% 2 4 3 2 3 3 4 5% 54%	2376
November	1st to 10th	Night	7% 5% 2 3 4 1 3 3 5% 7% 61%	2337
	11th to 20th	Night	9% 5% 2 4 4 3 4 4 5% 7% 55%	2470
	21st to end	Night	11% 7% 3 4 4 2 3 4 5% 5% 53%	2626
December	1st to 10th	Night	8% 7% 2 5% 5% 3 4 3 6% 6% 50%	2660
	11th to 20th	Night	9% 9% 3 6% 3 3 3 3 5% 6% 49%	3279
	21st to end	Night	16% 14% 7% 11% 5% 2 2 3 3 4 33%	4592

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	54% 7% 11% 18% 9% 1	2848
	11th to 20th	Day	50% 5% 13% 20% 12% 1	2850
	21st to end	Day	51% 5% 12% 18% 13% 1	3135
February	1st to 10th	Day	47% 5% 15% 20% 10% 3	1710
	11th to 20th	Day	41% 6% 12% 24% 14% 3	1730
	21st to end	Day	37% 6% 12% 25% 17% 4	1570
March	1st to 10th	Day	38% 6% 10% 24% 18% 3	2021
	11th to 20th	Day	48% 5% 9% 21% 15% 2	1980
	21st to end	Day	54% 6% 12% 18% 8% 2	2178
April	1st to 10th	Day	40% 4 13% 22% 17% 3	2021
	11th to 20th	Day	42% 6% 13% 24% 15% 1	2202
	21st to end	Day	45% 6% 10% 27% 11% 1	2340
May	1st to 10th	Day	46% 8% 11% 19% 14% 1	2340
	11th to 20th	Day	41% 7% 14% 25% 13%	2306
	21st to end	Day	45% 9% 13% 20% 10% 2	2531
June	1st to 10th	Day	28% 9% 14% 32% 16% 2	2430
	11th to 20th	Day	30% 8% 14% 28% 18% 2	2520
	21st to end	Day	28% 8% 16% 28% 15% 4	2370
July	1st to 10th	Day	30% 9% 15% 27% 16% 3	2276
	11th to 20th	Day	27% 8% 14% 27% 19% 4	2271
	21st to end	Day	29% 8% 16% 30% 17% 2	2405
August	1st to 10th	Day	33% 11% 16% 25% 13% 2	2314
	11th to 20th	Day	31% 6% 12% 30% 20% 2	2301
	21st to end	Day	27% 7% 12% 26% 21% 7%	2512
September	1st to 10th	Day	31% 6% 13% 25% 20% 5%	2079
	11th to 20th	Day	32% 6% 12% 25% 23% 2	1980
	21st to end	Day	30% 4 8% 32% 25% 2	1980
October	1st to 10th	Day	32% 6% 12% 25% 23% 2	1846
	11th to 20th	Day	30% 4 8% 26% 26% 6%	1800
	21st to end	Day	35% 4 12% 23% 19% 6%	1980
November	1st to 10th	Day	27% 5% 12% 29% 21% 4	1737
	11th to 20th	Day	32% 3 9% 29% 23% 3	1710
	21st to end	Day	37% 4 10% 27% 20% 2	1549
December	1st to 10th	Day	36% 6% 15% 28% 14% 1	1520
	11th to 20th	Day	41% 5% 14% 28% 11% 1	1915
	21st to end	Day	60% 5% 9% 17% 8% 1	3070
January	1st to 10th	Night	49% 6% 12% 20% 12% 1	4108
	11th to 20th	Night	43% 5% 12% 24% 15% 1	4120
	21st to end	Night	47% 5% 15% 20% 12% 2	4532
February	1st to 10th	Night	45% 5% 12% 19% 15% 4	2470
	11th to 20th	Night	38% 6% 12% 25% 15% 4	2365
	21st to end	Night	35% 5% 11% 22% 20% 8%	1884
March	1st to 10th	Night	34% 6% 11% 27% 18% 4	2053
	11th to 20th	Night	41% 5% 11% 22% 17% 4	1980
	21st to end	Night	51% 6% 12% 19% 10% 2	2178
April	1st to 10th	Night	33% 5% 12% 25% 21% 4	1937
	11th to 20th	Night	38% 6% 9% 28% 16% 3	1705
	21st to end	Night	40% 6% 11% 24% 18% 1	1620
May	1st to 10th	Night	43% 8% 13% 20% 15% 2	1620
	11th to 20th	Night	36% 7% 14% 24% 19%	1594
	21st to end	Night	36% 9% 18% 23% 12% 2	1746
June	1st to 10th	Night	22% 8% 16% 35% 15% 3	1522
	11th to 20th	Night	23% 7% 15% 32% 17% 5%	1440
	21st to end	Night	20% 6% 16% 33% 22% 4	1579
July	1st to 10th	Night	26% 7% 16% 27% 19% 4	1575
	11th to 20th	Night	20% 5% 15% 29% 26% 5%	1566
	21st to end	Night	23% 8% 14% 34% 19% 1	1673
August	1st to 10th	Night	24% 8% 18% 30% 18% 2	1601
	11th to 20th	Night	25% 7% 14% 31% 21% 2	1600
	21st to end	Night	24% 6% 12% 28% 21% 9%	1844
September	1st to 10th	Night	26% 6% 11% 27% 22% 7%	1878
	11th to 20th	Night	27% 6% 10% 31% 24% 4	1980
	21st to end	Night	24% 4 10% 26% 32% 3	1980
October	1st to 10th	Night	32% 6% 10% 25% 23% 4	2095
	11th to 20th	Night	29% 4 8% 26% 24% 8%	2160
	21st to end	Night	34% 4 10% 23% 25% 4	2376
November	1st to 10th	Night	24% 4 12% 27% 26% 6%	2337
	11th to 20th	Night	29% 5% 11% 29% 22% 4	2470
	21st to end	Night	33% 4 11% 27% 22% 3	2626
December	1st to 10th	Night	34% 6% 12% 29% 17% 1	2660
	11th to 20th	Night	37% 4 11% 32% 15% 1	3281
	21st to end	Night	57% 4 9% 21% 8% 2	4592

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	17% 16% 38% 20% 8% 1	270
	11th to 20th	Day	20% 19% 37% 20% 4	270
	21st to end	Day	15% 12% 44% 26% 3	297
February	1st to 10th	Day	16% 23% 43% 16% 3	270
	11th to 20th	Day	14% 17% 45% 19% 5% 1	270
	21st to end	Day	12% 19% 49% 17% 3	225
March	1st to 10th	Day	14% 14% 47% 23% 2	255
	11th to 20th	Day	26% 17% 31% 18% 6% 1	240
	21st to end	Day	26% 25% 35% 11% 2 1	264
April	1st to 10th	Day	20% 15% 40% 21% 5%	281
	11th to 20th	Day	18% 17% 38% 22% 5%	480
	21st to end	Day	23% 18% 31% 19% 10% 1	600
May	1st to 10th	Day	18% 12% 37% 23% 8% 1	603
	11th to 20th	Day	19% 12% 30% 26% 11% 3	625
	21st to end	Day	19% 10% 28% 27% 13% 3	679
June	1st to 10th	Day	5% 4 26% 32% 27% 7%	630
	11th to 20th	Day	7% 4 33% 35% 18% 4	630
	21st to end	Day	7% 7% 35% 36% 13% 2	630
July	1st to 10th	Day	9% 3 15% 35% 28% 10%	621
	11th to 20th	Day	6% 4 20% 41% 24% 6%	618
	21st to end	Day	7% 1 17% 42% 29% 4	684
August	1st to 10th	Day	8% 3 17% 41% 28% 4	626
	11th to 20th	Day	8% 3 19% 42% 23% 4	615
	21st to end	Day	10% 3 17% 32% 32% 5%	631
September	1st to 10th	Day	12% 3 20% 40% 22% 3	369
	11th to 20th	Day	6% 4 23% 40% 21% 5%	270
	21st to end	Day	14% 7% 33% 30% 14% 1	270
October	1st to 10th	Day	20% 9% 26% 27% 14% 5%	270
	11th to 20th	Day	9% 17% 44% 22% 6% 2	270
	21st to end	Day	18% 16% 37% 20% 7% 2	297
November	1st to 10th	Day	12% 13% 39% 24% 11% 1	270
	11th to 20th	Day	16% 17% 40% 22% 6%	270
	21st to end	Day	20% 11% 35% 24% 8% 1	270
December	1st to 10th	Day	9% 13% 42% 28% 6% 1	270
	11th to 20th	Day	17% 17% 33% 28% 6%	270
	21st to end	Day	21% 17% 42% 18% 3	297
January	1st to 10th	Night	11% 14% 39% 30% 7%	950
	11th to 20th	Night	12% 15% 40% 28% 5% 1	950
	21st to end	Night	14% 10% 43% 28% 4	1045
February	1st to 10th	Night	15% 11% 45% 25% 3	950
	11th to 20th	Night	15% 13% 40% 28% 4	890
	21st to end	Night	15% 13% 44% 22% 4	628
March	1st to 10th	Night	12% 15% 43% 23% 5%	569
	11th to 20th	Night	19% 12% 37% 27% 5%	540
	21st to end	Night	24% 13% 39% 19% 5%	594
April	1st to 10th	Night	14% 11% 47% 23% 5%	540
	11th to 20th	Night	16% 14% 38% 28% 4	533
	21st to end	Night	19% 10% 40% 25% 6% 1	540
May	1st to 10th	Night	16% 11% 33% 31% 8%	540
	11th to 20th	Night	16% 8% 31% 35% 10% 1	531
	21st to end	Night	14% 6% 29% 36% 14% 1	584
June	1st to 10th	Night	6% 5% 23% 43% 21% 1	540
	11th to 20th	Night	7% 3 30% 45% 15%	540
	21st to end	Night	5% 3 35% 45% 11%	540
July	1st to 10th	Night	6% 3 18% 46% 27% 1	525
	11th to 20th	Night	4 2 20% 51% 22% 2	522
	21st to end	Night	6% 2 15% 51% 26% 1	591
August	1st to 10th	Night	4 1 19% 50% 25% 2	537
	11th to 20th	Night	7% 2 17% 48% 25% 2	534
	21st to end	Night	7% 2 17% 44% 27% 3	594
September	1st to 10th	Night	11% 3 24% 41% 18% 2	540
	11th to 20th	Night	10% 2 28% 40% 19% 2	540
	21st to end	Night	8% 6% 33% 37% 14% 1	540
October	1st to 10th	Night	15% 6% 30% 34% 13% 2	655
	11th to 20th	Night	15% 10% 40% 27% 8%	720
	21st to end	Night	18% 11% 34% 29% 7%	792
November	1st to 10th	Night	9% 12% 34% 34% 11%	857
	11th to 20th	Night	11% 13% 41% 28% 6%	950
	21st to end	Night	15% 12% 36% 30% 7%	950
December	1st to 10th	Night	12% 14% 38% 29% 6% 1	950
	11th to 20th	Night	16% 12% 39% 28% 5%	950
	21st to end	Night	16% 16% 38% 25% 5%	1045

Page generated at 2024-03-03 05:28:59. Version ac07

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